Independent mattress units with transition zone

ABSTRACT

A mattress includes a first spring unit having a first degree of firmness, a second spring unit having a second degree of firmness different from the first degree of firmness, and a transition zone that is disposed between the first and second spring units. A foam perimeter surrounds the first and second spring units and the transition zone. The transition zone has a first row of springs adjacent to the first spring unit and has a degree of firmness between the first and second degrees of firmness that is closer to the first degree of firmness than the second degree of firmness. The transition zone also has a second row of springs adjacent to the second spring unit and has a degree of firmness between the first and second degrees of firmness that is closer to the second degree of firmness than the first degree of firmness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/348,233, filed May 25, 2010.

FIELD OF THE INVENTION

The invention relates to mattress systems having separate mattresssupport units of the same or varying firmnesses and a transition zonethat provides an area of transitional support between the mattresssupport units.

BACKGROUND OF THE INVENTION

Spring coil mattresses have been known in the art for many years. Avariety of attempts have been made to provide mattresses that havedifferent firmness zones within the same mattress. An example of such amattress is described in U.S. Patent Publication No. 2008/0072382 toJames. This patent application describes a mattress that has a foamperimeter surrounding two sections with a flexible spacer placed betweenthe two sections, the flexible spacer being constructed of foam. Arraysof springs are placed in the two sections and the foam flexible spaceris described as restricting translation of movement between the adjacentsections of the mattress. This flexible spacer is also described asbeing rather small, generally significantly less than the width of theperimeter rail.

Another attempt at providing a mattress with varying firmness is ahybrid mattress having portions with different support characteristics,as described in U.S. Pat. No. 5,740,574 to Piraino. This hybrid mattressis described as having two individual support means with differentialdeflection coefficients, such as two inner spring supports, and acomfort means which is a unitary casing of foam rubber having twopouches sized to snugly receive the individual support means. Thiscasing structure of the comfort means is described as also having aninternal interface member. The internal interface member is described asa piece of rigid foam connecting the top and bottom surface members andcreating the two pouches in which the individual support means fit. Theinterface member is further described as being part of the unitarycomfort means that allows the hybrid mattress to act as a single unitwithout coming apart or shifting during use. This foam interface memberwhich is part of the casing structure is stated to alleviate problems inthe prior art of traversing the change in support rating from one unitto the other.

These prior attempts at creating a mattress rely on a piece of foam thatacts as a flexible spacer or interface member to separate the twosupport units.

SUMMARY OF THE INVENTION

An embodiment of the present invention are directed to a mattress thathas two independent mattress units with support characteristics thatdiffer from one another, and that has a transition zone disposed betweenthe two mattress units. Each of the independent mattress units can be anarray of springs that has a degree of firmness that is different fromthe degree of firmness of the other independent mattress unit. Thetransition zone is formed by one or more rows of compression of springshaving a degree of firmness that is between the degrees of firmness ofthe two mattress units.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present invention will now be described by referencewith the following figures, in which:

FIG. 1 is a diagram of a conventional multi-firmness mattress having twocoil units of different firmness, with a thin foam separator rail.

FIG. 2 shows an embodiment of the invention in which a mattress has twoindependent mattress units of different firmnesses with a transitionzone of two rows of springs each with a different firmness between thefirmness of the two independent mattress units.

FIGS. 3(A)-3(D) illustrate a plurality of mattress units with differentfirmnesses.

FIGS. 4(A)-4(F) show various transition zone spring units having morethan one row of springs with each row having either the same or adifferent firmness than the firmness of the other row.

FIGS. 5(A)-5(J) show various configurations of a mattress havingindependent mattress units of the same or differing firmnesses with atransition zone of springs disposed therebetween.

FIG. 6 is a flowchart illustrating the steps in a method to make amattress that has two independent mattress units of different firmnesseswith a transition zone disposed therebetween, according to an embodimentof the invention.

DETAILED DESCRIPTION

FIG. 1 shows a conventional mattress 100 in the related art that has afoam casing made up of side rails 101 a and 101 b, head rail 101 c, andfoot rail 101 d, and two spring units 102 and 103 of differentfirmnesses, which are support units for supporting a person duringsleep. Disposed between the spring units is a thin foam rail 104.

A well known type of bedding employs a spring assembly that includes anumber of discrete coil springs, each of which is enclosed in a fabricpocket in a length of folded fabric material. Longitudinal axes of thecoil springs are generally parallel with one another so that the top andbottom end turns of the coil springs define top and bottom faces of thespring assembly. A row of such pocketed springs is known in the industryas a string of pocketed springs. A bedding product can be fabricatedfrom such strings of pocketed springs by binding or adhering theindividual rows or strings of pocketed springs together to form a springassembly which may be padded and encased in an upholstered covering.This type of spring assembly is commonly referred to as a pocketedspring assembly due to the fact that each spring is contained within anindividual pocket of fabric material. The construction of strings ofpocketed coil springs in each pocket is well known in the art and, forexample, is disclosed in U.S. Pat. No. 4,439,977, which is herebyincorporated by reference in its entirety. The system disclosed in thatpatent includes a spring coiler which forms a coil spring which issubsequently compressed and inserted between the plies of foldedpocketing fabric material.

For ease of description, and without limitation, different firmnesses ofthe springs are assigned the name of a color and will be referred to bythat color. For example, spring units made of 14 gauge wire will bereferred to by the color red (R). Spring units made of 14.5 gauge wirewill be referred to by the color blue (B). Spring units made of 15 gaugewire will be referred to by the color green (G). Spring units made of 16gauge wire will be referred to by the color tan (T). Generally, thelarger the gauge of wire from which a spring is constructed, the firmerthe spring and more support is will provide. It will be understood thatthe gauges of wire described here are merely examples and other gaugescan be used.

FIG. 2 shows a mattress 200 according to an embodiment of the presentinvention which has two independent mattress units of differentfirmnesses with a transition zone having two rows of springs. Themattress 200 is formed by a foam perimeter made up of side rails 201 aand 201 b, a head rail 201 c, and a foot rail 201 d. A first spring unit202 is a support unit that has a first firmness made of a plurality ofstrings of pocketed springs with coils of 16 gauge wire and is referredto as a tan spring unit. A second spring unit 203 is a support unit thatis formed of a plurality of strings of pocketed springs with coils madefrom a heavier gauge wire, namely 14 gauge wire, and therefore is firmerthan spring unit 202, and is referred to as a red spring unit. Atransition zone of springs 204 is formed from two transition strips 204a and 204 b which, according to the present embodiment, are strings ofpocketed springs, each string of pocketed springs also being referred toas a row of springs, with firmnesses that transition from a firmerspring (blue) to a softer spring (green). Together the two transitionspring rows 204 a and 204 b form the transition zone. The firmer row ofsprings in the transition zone, in this case the blue row of springs 204b, is disposed adjacent to the firmer spring unit, namely the red springunit 203. The less firm, or softer row of springs in the transitionzone, in this case the row of green springs 204 a, is disposed adjacentto the softer spring unit, namely the tan spring unit 202.

The transition zone springs 204 can be attached to either one or both ofthe spring units 202, 203 by conventional methods, such as by gluing orhog-ringing. The transition zone is attached to at least one of thespring units prior to the spring units being inserted into the spaceformed by the foam perimeter 201 a-201 d. The foam perimeter surroundsthe spring units 202, 203 and the transition zone 204. The mattress 200is then covered by suitable top covering materials to form a mattresssuitable for use by two people. Accordingly, the resulting mattress withindependent spring units is suitable for a person desiring a relativelyfirm mattress, corresponding to the spring unit made of heavier gaugewire such as red spring unit 203, and by a person desiring a less firm,or softer mattress corresponding to the spring unit made of lightergauge wire such as tan spring unit 202. And the mattress has atransition zone 204 that has a firmness that transitions in a relativelycontinuous manner from the firmer spring unit (red) to the softer springunit (tan), making the change in firmness between the spring units lessnoticeable than in conventional mattresses.

The mattress can be a suitable size for comfortable sleeping by twopeople, such as a king or queen size mattress. However, the techniquesdescribed here can be used with other size mattresses.

Selection of the appropriate spring units can be made in conjunctionwith automatic mattress recommendation systems such as those describedin U.S. Pat. Nos. 6,571,192, 6,741,950, and 6,990,425 to Hinshaw, etal., which are incorporated herein by reference. Based on customers'selection or recommendation of the appropriate firmness for each side ofthe mattress, a suitable mattress can be built using the appropriatespring units with the selected or recommended firmness for each person.Based on the spring units to be used in the mattress, a transition zoneis determined that appropriately blends the firmness from one side ofthe mattress to the other. The transition zone, according to the presentembodiment, has two rows of springs with the firmness of the springs ineach row selected based on the firmness of the different mattress units.The firmness of the coils making up the transition zone are selected toprovide a gradual transition from the firmness of one mattress unit tothe firmness of the other mattress unit. In the following embodiment,the firmnesses ranges from the most firm, being a 14 gauge red (R)spring coil, to a 14.5 gauge blue (B) spring coil, to a 15 gauge green(G) spring coil, to the softest spring coil, tan (T), made of a 16 gaugewire. As illustrated in FIGS. 3(A)-3(D), mattress units, or supportunits, are made of a plurality of strings of pocketed springs in whichthe springs are coils of the same firmness. For example, FIG. 3(A) showsa spring unit made of ten strings of pocketed springs connected togetheras a spring unit. Each of the springs in the spring unit shown in FIG.3(A) is a tan (T) type spring of 16 gauge wire making the spring unitshown in FIG. 3(A) the softest spring unit of the present embodiment.FIG. 3(B) shows a somewhat firmer spring unit made of a plurality ofstrings of pocketed springs in which the springs are made of green (G)springs of 15 gauge wire. FIG. 3(C) shows an even firmer spring unitmade of a plurality of strings of pocketed springs in which the springsare made of blue (B) springs of 14.5 gauge wire. And FIG. 3(C) shows anthe firmest spring unit made of a plurality of strings of pocketedsprings in which the springs are made of red (R) springs of 14 gaugewire.

The spring coils used to make the transition zone rows are selected tohave a firmness that transitions from the firmness of one of themattress units to the firmness of the other mattress unit. For example,the mattress shown in FIG. 2 has a relatively soft tan (T) mattress unit202 made of 16 gauge wire. Red (R) mattress unit 203 is made of 14 gaugespring coils. The transition zone is formed by a row of blue (B) springs204 b of 14.5 gauge wire and a row of green (G) springs 204 a of 15gauge wire. The row of blue springs is disposed next to the firmermattress unit, the red (R) unit 203, and the row of green springs isdisposed next to the softer mattress unit, the tan (T) unit 202. Thisprovides an gradual easing of the firmness of coils going from thefirmer side of the mattress to the softer side of the mattress, that is,going from the red (R) mattress unit to the tan (T) mattress unit. Thisresults in a more subtle transition from the firm mattress unit to thesofter mattress unit, and is more pleasing and desirable to the usersthan in conventional mattress support structures having differingfirmnesses. In the mattress shown in FIG. 2, the blue and green rows ofsprings in the transition zone have a firmness that is between thefirmness of the red and tan spring units and therefore provides for acontinuous transition in firmness in the transition zone 204.

The different firmnesses of the spring units, described here as red,blue, green and tan, can be considered degrees of firmness. A red springunit and a blue spring unit differ by one degree of firmness. Similarly,a red spring unit and a green spring unit differ by two degrees offirmness. And a red spring unit and a tan spring unit differ by threedegrees of firmness Likewise, a blue spring unit and a green spring unitdiffer by one degree of firmness, and a blue spring unit and a tanspring unit differ by two degrees of firmness. And a green spring unitand a tan spring unit differ by one degree of firmness. Similarly, rowsof springs for the transition zone differ in degrees of firmness in thesame manner.

In general, the degrees of firmness of the springs used in the rows ofthe transition zone are chosen to provide a gradual change in firmnessthat is as continuous as possible, going from one spring unit toanother. There are some configurations where either one of two degreesof firmness can be chosen to provide this gradual or near-continuoustransition. In certain embodiments of the invention, when such a choiceis to be made, the firmer degree of spring is chosen. The firmer row ofsprings is chosen because the person desiring firmer support often willbe the larger of the two partners using the mattress and may requiremore mattress area.

FIGS. 4(A)-4(F) show various configurations of rows of springs for atransition zone. For example, six different transition zones are shownin these figures: two rows of tan springs shown in FIG. 4(A), two rowsof green springs shown in FIG. 4(B), two rows of blue springs shown inFIG. 4(C), two rows of red springs shown in FIG. 4(D), one row of greensprings with one row of blue springs shown in FIG. 4(E), and one row ofblue springs with one row of red springs shown in FIG. 4(F).

Various combinations of mattress units and transition zones are shown inFIGS. 5A-J.

FIG. 5A shows a configuration with two green mattress units which haveno difference in firmness and therefore the transition zone is formedfrom two rows of green springs. FIG. 5B shows the configuration shown inFIG. 2, in which the mattress units differ by three degrees of firmness.Accordingly, the transition zone is formed by a row of blue springspositioned adjacent to the red spring unit, and a row of green springspositioned adjacent to the tan spring unit. FIG. 5C shows aconfiguration with a blue mattress unit and a tan mattress unit, whichdiffer by two degrees of firmness. Because only one type of spring has afirmness between the firmness of the blue and the tan spring units,namely a green spring unit, the row of coils in the transition zonedisposed closest to the firmer mattress unit, namely the blue mattressunit, is chosen to be the same as the firmer mattress unit. So in thiscase, a blue row of springs is selected for the transition zone to bepositioned next to the blue mattress unit. This is because the firmermattress unit is likely to support a larger size person who may needmore area on the mattress for firm support. A green coil is selected forthe second row of the transition zone and it is positioned next to thetan unit to provide a transition from blue to tan. In FIG. 5D, green andtan mattress units are selected. Since those two mattress units areadjacent in degrees of firmness, both rows of springs of the transitionzone are selected to be the same firmness as the more firmer mattressunit, namely green springs. This provides more area for the persondesiring the firmer coil mattress.

The remaining mattresses shown in FIGS. 5(E)-(J) show variouscombinations and configurations of spring units and transition zones.

A method of making a mattress with a plurality of support zones ofdifferent firmnesses and a transition zone between the support zones, isillustrated in FIG. 6. In this method, a mattress is made with twosupport zones suitable for supporting two people, in which each supportzone supports one of the two people according to that person's physicaland sleep characteristics. In step 601, the first person's physical andsleep characteristics are analyzed. For example, the techniquesdescribed in U.S. Pat. Nos. 6,571,192, 6,741,950, and 6,990,425 toHinshaw, et al., can be used to analyze the person's physical and sleepcharacteristics. In the present embodiment, a computer programmed withan algorithm as described in those patents, and incorporated herein byreference, performs the analysis. In step 602, a similar analysis isperformed for the second person. In step 603, a first support unit,having a first firmness, is selected according to the analysis of thefirst person's physical and sleep characteristics. In step 604, a secondsupport unit, having a second firmness, is selected according to theanalysis of the second person's physical and sleep characteristics. Instep 605, a transition zone, having two transition strips, is selectedbased on the selected first and second support units. The firmness ofthe transition strips is selected according to the guidance describedabove. The transition strips can be connected to one another to form thetransition zone. Each transition strips can be a string of pocketedsprings.

The transition zone is then connected to at least one of the supportunits, such as the first support unit, as shown in step 606. In step607, the components of the mattress are arranged such that the selectedtransition zone is disposed between the first and second support unitswith the firmer transition strip of the transition zone being placedadjacent to the firmer support unit In step 608, a foam perimeter isplaced around the arranged first support unit, transition zone, andsecond support unit. The assembly is covered with one or more layers ofmattress covering materials.

The present invention is not restricted to spring coil type supportmembers but can use other types of members as well such as foam mattressunits, etc. For example, the support units can be made of foam rubberhaving the appropriate firmness and the transition strips also can beformed of foam rubber having the appropriate firmness. In embodimentsusing coils, the coils can be made from any type of suitable innerspring type coil conventionally used for sleep products such as pocketedcoils, a Bonnell coil or other continuous wire units, although theinvention is not limited to these type of coils. Combinations of typesof support units and transition strips can be used depending on theapplication.

While the invention has been particularly shown and described withreference to certain embodiments thereof, it would be understood bythose skilled in the art that various changes in form and detail may bemade without departing from the spirit and scope of the invention.

What is claimed is:
 1. A mattress comprising: a first spring unit havinga first degree of firmness; a second spring unit having a second degreeof firmness different from the first degree of firmness; a transitionzone disposed between the first and second spring units; a foamperimeter surrounding the first and second spring units and thetransition zone; the transition zone comprising: a first row of springsadjacent to the first spring unit and having a degree of firmnessbetween the first and second degrees of firmness and closer to the firstdegree of firmness than the second degree of firmness; and a second rowof springs adjacent to the second spring unit and having a degree offirmness between the first and second degrees of firmness, and closer tothe second degree of firmness than the first degree of firmness.
 2. Themattress according to claim 1, wherein the first and second rows areeach a string of pocketed springs.
 3. A bedding product, comprising: afirst support unit having a first degree of firmness; a second supportunit have a second degree of firmness different from the first degree offirmness; a transition zone disposed between the first and secondsupport units; a perimeter zone surrounding the first and second supportunits and the transition zone; the transition zone comprising: a firsttransition strip adjacent to the first support unit and having a degreeof firmness between the first and second degrees of firmness and closerto the first degree of firmness than the second degree of firmness; anda second transition strip adjacent to the second support unit and havinga degree of firmness between the first and second degrees of firmness,and closer to the second degree of firmness than the first degree offirmness.
 4. The bedding product according to claim 3, wherein at leastone of the first and second support units is a spring unit comprised ofsprings.
 5. The bedding product according to claim 4, wherein at leastone of the spring units is comprised of a string of pocketed springs. 6.The bedding product according to claim 5 wherein at least one of thefirst and second transition strips is comprised of a string of pocketedsprings.
 7. The bedding product according to claim 3, wherein at leastone of the first and second transition strips is comprised of a stringof pocketed springs.
 8. A method of making a bedding product,comprising: selecting a first support unit having a first degree offirmness; selecting a second support unit have a second degree offirmness different from the first degree of firmness; making atransition zone by selecting a first transition strip having a degree offirmness between the first and second degrees of firmness and closer tothe first degree of firmness than the second degree of firmness, byselecting a second transition strip having a degree of firmness betweenthe first and second degrees of firmness, and closer to the seconddegree of firmness than the first degree of firmness, and by disposingthe first and second transition strips adjacent to one another; anddisposing the transition zone between the first and second support unitswherein the first transition strip is disposed adjacent to the firstsupport unit and the second transition strip is disposed adjacent to thesecond support unit.
 9. The method according to claim 8, wherein atleast one of the first and second support units is a spring unitcomprised of springs.
 10. The method according to claim 9, wherein atleast one of the spring units is comprised of a string of pocketedsprings.
 11. The method according to claim 10, wherein at least one ofthe first and second transition strips is comprised of a string ofpocketed springs.
 12. The method according to claim 8, wherein at leastone of the first and second transition strips is comprised of a stringof pocketed springs.